The present invention relates to an apparatus for shaping a laser beam, and more particularly, for shaping a laser beam having an annular cross-section, in order to provide a more uniform heat distribution at a work station.
It is well known to use high powered carbon dioxide lasers for industrial metal working applications such as heat treating, cutting, welding, shaping and the like. In such applications, the metal piece to be operated upon is moved in a predetermined relationship with respect to the laser beam at a work station. In this way, the residence time and area of coverage is controlled in accordance with desired programming. However, difficulties have been encountered with such industrial laser systems because of the configuration of the laser beam itself and its energy distribution, particularly when such lasers are used for heat treating.
For example, laser beams are generally circular in cross-section, and the high powered carbon dioxide lasers now employed generally for heat treating and the like have an annular shape or ring-like cross-section. This causes a greater concentration of energy along the outer edges of the heat treated area than in the middle portion, thereby causing uneven heat treatment of the piece part being operated upon.
It is therefore seen that a problem exists in the high powered laser beam art, and that improvements are needed in order to effect a more uniform heat distribution on work pieces, which are to be operated upon by such lasers. Accordingly, the present invention is directed toward a solution to such problems.